1. Field of the Invention
The present invention relates to saboted projectiles capable of being fired from airplanes wherein the sabot does not disintegrate after firing but rather follows a predictable trajectory so that there is no substantial chance of ingestion of the sabot or any part thereof into the airplane engine or collision of the plane with a sabot or any part thereof.
2. Description of the Prior Art
The prior art includes about 1,000 patents relating to saboted projectiles. None of these are capable of being fired from an airplane because none of the prior art discloses a practical saboted projectile having a sabot which after separation from the penetrator describes a predictable trajectory carrying the sabot initially forward of the airplane then downward in relation to the airplane so that the sabot is always below the airplane by the time the airplane catches up with the decelerating sabot. Typically prior art sabots disintegrate which is no problem when fired from a platform not moving at high speeds.
Accordingly, there are no saboted projectiles disclosed by the prior part which are capable of being fired from an airplane. Modern guns may fire 100 projectiles per second. If 100 sabots per second disintegrate in front of an airplane, the particles from the sabots move in relatively random directions within a relatively wide cone in front of the plane. There is a substantial chance that one or more of these articles will collide with the plane or be ingested into the plane's engine. Accordingly, prior art sabots are too hazardous to the airplane to be fired from the plane.
A saboted projectile comprises a sub-caliber penetrator relatively dense in relation to cross-sectional area projectile which must be separated from a low mass, low density, in relation to cross-sectional area, sabot after leaving the gun barrel. The shape of the unseparated sabot/penetrator combination is not one that one would normally use for accuracy. In addition, there are relatively minor but inherent problems associated with accuracy which result from separation of the sabot from the penetrator. The quicker the penetrator separates from the sabot and the less mechanical contact between the sabot and the penetrator during separation and the more uniform the separation point of the sabot from the penetrator is in relation to the muzzle during firing, the more accurate is the penetrator likely to be. Doing the same thing the same way each time is a good strategy for maintaining accuracy and precision. If a sabot is to be assembled by screwing in a threaded end plate, a procedure which is useful for manufacturing purposes, there is a chance that the threading may become slightly loosened during storage or loading of the projectile. Loading may subject the projectile to forces in excess of 2,000 g' s which could loosen or change the tightness of a screwed in part. Accordingly, accuracy would be increased if there were someway to ensure uniform tightening of the threads before the projectile leaves the barrel but after it is fired.
Practically none of the elements claimed in the present invention are found in the prior arts. A search of the appropriate classes found a ring used, which ring had a slit and a notch at the opposite end to make expansion of the ring easier, but the ring was not actually balanced when rotated so as to expand the prior art ring and unbalanced when not rotated at high rotational velocity. The prior art discloses no sabot capable of being fired from an airplane in a forward direction, without danger to the airplane from possible ingestion of a part of the sabot. The prior art discloses no sabot capable of following a predictable trajectory guaranteed to keep the sabot away from a strafing airplane which must remain within 150 feet of the terrain to avoid return fire. The prior art discloses no sabot capable of remaining ahead of the airplane for 4 to 5 seconds at airplane speeds of about 300 knots and 2 to 3 seconds at airplane velocity of 500 knots, thereby insuring that the sabot will be very close to the ground when the plane catches up to the sabot. The prior art discloses no such sabot substantially maintaining its shape between leaving the barrel and separating from the penetrator and impact.